Submission #989731

#	Time	Username	Problem	Language	Result	Execution time	Memory
989731		Ralph_J	Tracks in the Snow (BOI13_tracks)	C++17	2.19 / 100	3868 ms	1048576 KiB

tracks

// #pragma GCC optimize("Ofast, unroll-loops, no-stack-protector, fast-math, O3, omit-frame-pointer, inline, avx, avx2, fma")
#include <bits/stdc++.h>
using namespace std;
#define SZ(x) ((int)(x).size()) // size of a container
#define F(i, n) for (int i = 0; i < (int)(n); i++) 
#define ALL(a, x) memset(a, x, sizeof(a)) // set elements of array to some value
#define max(a, b) ((a) > (b) ? (a) : (b))
#define min(a, b) ((a) < (b) ? (a) : (b))
#define REMAX(a, b) (a) = max((a), (b)) // set a to the maximum of a and b
#define REMIN(a, b) (a) = min((a), (b));
#define FOREACH(i, t) for (typeof(t.begin()) i = t.begin(); i != t.end(); i++) // traverse an STL data structure
#define all(c) (c).begin(), (c).end() // handy for function like "sort()"
#define contain(c, x) ((c).find(x) != (c).end())
#define present(c, x) (count(all(c), x)>0)
typedef long long ll; // data types used often, but you don't want to type them time by time
typedef unsigned long long ull;
const long double PI = 3.1415926535897932384626;
const int mod = 1000000007;
#define dbg(var) cerr << #var << " = " << (var) << endl; // for debug
#define pb push_back // for vectors
#define SORT(p) sort(all(p))
#define REVERSE(p) reverse(all(p))
#define onecount __builtin_popcount // count number of 1's in a number
#define highbit(x) (63 - __builtin_clzll(x)) // get the index of the highest bit set
#define lowbit(x) __builtin_ctzll(x) // get the index of the lowest bit set
#define bitcount(x) (__builtin_popcount(x) + __builtin_popcount(x >> 32)) // count number of 1's in a number in O(1) time
#define mid(l, r) ((l) + (((r) - (l)) >> 1))
typedef int elem_t;
template <typename T, typename TT>
ostream &operator<<(ostream &s, pair<T, TT> t) { return s << "(" << t.first << "," << t.second << ")"; }
template <typename T>
ostream &operator<<(ostream &s, vector<T> t){ F(i, SZ(t)) s << t[i] << " ";return s;}
template <typename T>
istream &operator>>(istream &in, vector<T>&e){for(auto&x : e) cin >> x; return in;}
template <typename T, typename TT>
istream &operator>>(istream &in, vector<pair<T, TT>>&e){for(auto&x : e) cin >> x.first >> x.second; return in;} 
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
ll largest_multiple_smaller_than_x(ll a, ll k){ return (k / a) * a;}
ll smallest_multiple_greater_than_x(ll a, ll k){ return ((k + a - 1) / a) * a;}
vector<ll>sieve(ll num){vector<ll>prime;vector<bool>isPrime(num + 1, true);isPrime[0] = isPrime[1] = false;for(int i = 2; i <= num; i++){if(isPrime[i]){prime.push_back(i);for(int j = i * 2; j <= num; j += i) isPrime[j] = false;}}return prime;}
#define int long long
vector<int>primeFactors(int num){vector<int>prime;for(int i = 2; i * i <= num; i++){while(num % i == 0){prime.push_back(i);num /= i;}}{if(num > 1) prime.push_back(num);}return prime;}
bool is_prime(ll num){if(num < 2) return false;for(ll i = 2; i * i <= num; i++){if(num % i == 0) return false;}return true;}
vector<int>binary(ll num){vector<int>binary;while(num){binary.push_back(num % 2); num >>= 1;} reverse(all(binary)); return binary;}
int decimal(vector<ll>binary){ int num = 0; for(int i = 0; i < binary.size(); i++){num += binary[i] * (1 << i);}return num;}
ll factorial(ll num, ll mod = 1e9+7){ ll fact = 1; for(ll i = 1; i <= num; i++) fact = (fact * i) % mod; return fact;}
vector<int> divisors(int n){ vector<int> div; for(int i = 1; i * i <= n; i++){ if(n % i == 0){ div.push_back(i); if(i * i != n) div.push_back(n / i); } } return div; }
ll power(ll x, ll y, ll mod = 1e18+7){ll res = 1; x %= mod; while(y > 0){if(y & 1) res = (res * x) % mod; y >>= 1; x = (x * x) % mod;} return res;}
ll mod_inverse(ll num, ll mod = 1e9+7){ return power(num, mod - 2, mod);}
ll NchooseK(ll n, ll k, ll mod = 1e9+7){ll res = 1; k = min(k, n - k); for(ll i = 0; i < k; i++){ res = (res * (n - i)) % mod; res = (res * mod_inverse(i + 1, mod)) % mod;} return res;}

int n, m; 
void dfs(int pari, int parj, int i, int j, vector<string> & a, vector<vector<int>> & color, int cur_color){
    if(i < 0 || j < 0 || i >= n || j >= m || a[i][j] == '.' || color[i][j] != 0 || a[i][j] != a[pari][parj]) return;
    color[i][j] = cur_color;
    for(int x = -1; x <= 1; x++){
        for(int y = -1; y <= 1; y++){
            if(x * y != 0) continue;
            dfs(i, j, i + x, j + y, a, color, cur_color);
        }
    }
}

void solve(){
    cin >> n >> m;
    vector<string> a(n); cin >> a;

    vector<vector<int>> color(n, vector<int>(m, 0)); 
    int cur_color = 0;
    for(int i = 0; i < n; i++){
        for(int j = 0; j < m; j++){
            if(color[i][j] == 0 && a[i][j] != '.') cur_color++;
            dfs(i, j, i, j, a, color, cur_color);
        }
    }
    // for(auto e : color) cout << e << '\n';
    vector<set<int>> adj(cur_color);
    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            if(a[i][j] == '.') continue;
            if(i < n - 1 && a[i][j] != a[i + 1][j]){
                adj[color[i][j]].insert(color[i + 1][j]);
                adj[color[i + 1][j]].insert(color[i][j]);
            }
            if(j < m - 1 && a[i][j] != a[i][j + 1]){
                adj[color[i][j]].insert(color[i][j + 1]);
                adj[color[i][j + 1]].insert(color[i][j]);
            }
        }   
    }
    queue<pair<int,int>> Q; Q.push({1, 0});
    vector<int> vis(cur_color); vis[1] = 1;
    int res = 0;
    while(!Q.empty()){
        int root = Q.front().first;
        int d = Q.front().second;
        res = max(res, d);
        Q.pop();
        for(auto e : adj[root]){
            if(vis[e]) continue;
            vis[e] = 1;
            Q.push({e, d + 1});
        }
    }
    cout << res + 1 << '\n';
}

int32_t main()
{
    // freopen(".in","r",stdin);
    // freopen(".out","w",stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int TT = 1;
    // cin >> TT;
    while(TT--){
        solve();
    }
    return 0; 
}

Compilation message (stderr)

tracks.cpp: In function 'long long int decimal(std::vector<long long int>)':
tracks.cpp:46:62: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 | int decimal(vector<ll>binary){ int num = 0; for(int i = 0; i < binary.size(); i++){num += binary[i] * (1 << i);}return num;}
      |                                                            ~~^~~~~~~~~~~~~~~

• Subtask 1: 0 / 30
• Subtask 2: 2.1875 / 70